防止JInternalFrame移出JDesktopPane

Question

当我在JDesktopPane中有一个JInternalFrame时,JInternalFrame是可移动的(这很好).但是,可以将它移到JDesktopPane的可见范围之外(我不是很喜欢)

为了亲眼看看,这里有一些示例代码:

public static void main(String[] args) {

  JFrame frame = new JFrame("JDesktopPane");
  JDesktopPane tableDisplay = new JDesktopPane();

  JInternalFrame internalFrame = new JInternalFrame("JInternalFrame",true,true,true,true);
  internalFrame.setContentPane(new JLabel("Content"));
  internalFrame.pack();
  internalFrame.setVisible(true);
  tableDisplay.add(internalFrame, JDesktopPane.POPUP_LAYER);

  frame.setContentPane(tableDisplay);
  frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
  frame.setMinimumSize(new Dimension(400, 300));
  frame.setVisible(true);
}

是否可以设置JInternalFrame或JDesktopPane,以便它们不允许这样做？

Answer 1

负责移动/调整大小的协作者是DesktopPaneManager.所以我会尝试将移动限制在窗格内.这是一个快速而肮脏的概念证明:

    JDesktopPane background = new JDesktopPane();
    JInternalFrame internalFrame = new JInternalFrame("Internal Frame",
            true, true, true, true);
    DesktopManager manager = new DefaultDesktopManager() {
        /** This moves the <code>JComponent</code> and repaints the damaged areas. */
        @Override
        public void setBoundsForFrame(JComponent f, int newX, int newY, int newWidth, int newHeight) {
            boolean didResize = (f.getWidth() != newWidth || f.getHeight() != newHeight);
            if (!inBounds((JInternalFrame) f, newX, newY, newWidth, newHeight)) return;
            f.setBounds(newX, newY, newWidth, newHeight);
            if(didResize) {
                f.validate();
            } 
        }

        protected boolean inBounds(JInternalFrame f, int newX, int newY, int newWidth, int newHeight) {
            if (newX < 0 || newY < 0) return false;
            if (newX + newWidth > f.getDesktopPane().getWidth()) return false;
            if (newY + newHeight > f.getDesktopPane().getHeight()) return false;
            return true;
        }

    };
    background.setDesktopManager(manager);

有一些问题需要解决,显然:-) Fi

• 使用适用于LAF的管理器,这可以通过实现一个包装器DesktopManager来完成,该程序包将所有其他内容委托给安装的LAF
• 检查副作用(在撞墙后阻力似乎没有反应,可能还需要其他东西)

编辑

只是为了澄清:"没有反应"我的意思是用户必须释放并再次按下/拖动(一旦内部框架已经达到桌面边界)进一步移动.这并不奇怪,因为BorderListener(它是由BasicInternalFrame安装的mouseListener)保持一些与初始按下相关的状态,然后请求相对于该初始位置重新定位.拖动鼠标框架卡在某处会混淆内部状态.

有趣的是,看看代码,看起来有意图限制运动不要把它推到外面,

    // Make sure we stay in-bounds
    if(newX + i.left <= -__x)
        newX = -__x - i.left + 1;
    if(newY + i.top <= -__y)
        newY = -__y - i.top + 1;
    if(newX + __x + i.right >= pWidth)
        newX = pWidth - __x - i.right - 1;
    if(newY + __y + i.bottom >= pHeight)
        newY =  pHeight - __y - i.bottom - 1;

但这与当前鼠标位置有关.

Answer 2

完全归功于kleopatra让我指向正确的方向.

我想我已经解决了无反应问题,并且在这里分享我的解决方案.按照kleopatra的回答,如果鼠标点位于窗格之外,则内部框架位于窗格的边缘.此外,这继续跟随鼠标 - 即如果您将鼠标移离窗格底部,然后向窗口的右侧移动,则框架将沿着窗格的底部,然后向右移动窗格的沙子.

public class BoundedDesktopManager extends DefaultDesktopManager {

  @Override
  public void beginDraggingFrame(JComponent f) {
    // Don't do anything. Needed to prevent the DefaultDesktopManager setting the dragMode
  }

  @Override
  public void beginResizingFrame(JComponent f, int direction) {
    // Don't do anything. Needed to prevent the DefaultDesktopManager setting the dragMode
  }

  @Override
  public void setBoundsForFrame(JComponent f, int newX, int newY, int newWidth, int newHeight) {
    boolean didResize = (f.getWidth() != newWidth || f.getHeight() != newHeight);
    if (!inBounds((JInternalFrame) f, newX, newY, newWidth, newHeight)) {
      Container parent = f.getParent();
      Dimension parentSize = parent.getSize();
      int boundedX = (int) Math.min(Math.max(0, newX), parentSize.getWidth() - newWidth);
      int boundedY = (int) Math.min(Math.max(0, newY), parentSize.getHeight() - newHeight);
      f.setBounds(boundedX, boundedY, newWidth, newHeight);
    } else {
      f.setBounds(newX, newY, newWidth, newHeight);
    }
    if(didResize) {
      f.validate();
    }
  }

  protected boolean inBounds(JInternalFrame f, int newX, int newY, int newWidth, int newHeight) {
    if (newX < 0 || newY < 0) return false;
    if (newX + newWidth > f.getDesktopPane().getWidth()) return false;
    if (newY + newHeight > f.getDesktopPane().getHeight()) return false;
    return true;
  }
}